This invention relates to a cable connecting and disconnecting apparatus for submerged pumps.
In general, when a submerged pump is installed or removed during the maintenance operation and inspection therefor, the power cable is connected and disconnected.
Referring to FIG. 2 showing an overall view of a submerged pump, a cable connecting and disconnecting apparatus 10 for the submerged pump is provided on an outer side of a submerged pump body 12 and so formed that liquid side and atmosphere side power cables are connected together through an intermediate container 14.
In a conventional cable connecting and disconnecting apparatus 10 as shown in FIG. 1, a reference numeral 14 denotes a cylindrical intermediate container. To opposite ends of this intermediate container 14, the liquid side and atmosphere side terminal headers 15 and 17 are connected by means of the bolts 18 through the covering plates 16 so that the intermediate container 14 may be separated at the liquid side terminal header 15 on the plane A shown in FIG. 1. The interior of the intermediate container 14 is closed airtightly by partitions 20 and 22, and an insulating tube 24 is fixed to one partition 20 and extends to within the other partition 22. A pin 26, one end of which is connected to three atmosphere side power cables, is inserted into the insulating tube 24.
A terminal 32 of the terminal pin 26 inserted into the intermediate container 14 and projecting from the liquid side partition 20 is fixed with a liquid side power cable 30 by means of bolts 33 and is housed in and protected by an insulating tube 28 fixed to an end surface of the liquid side covering plate 16 for the intermediate container 14.
In order to withdraw the submerged pump from the water for the purpose of repairing and inspecting the same, such a conventional cable connecting and disconnecting apparatus 10 is subjected to an operation for disassembling the liquid side and atmosphere side terminal headers. During this operation, the insulating tube 28 is withdrawn until it is completely out of the liquid side terminal header 15 after the bolts 18 with which the intermediate container is fastened to the same terminal header were removed. Before the liquid side power cables 30 connected to the three terminals 32 are removed, the insulating tube 28 must be removed. Finally, the bolt 33 engaged with the terminal 32 at the end of the terminal pin 26 are withdrawn at right angles to the axis of the cable to complete the disassembling operation.
Since an excessively large load is borne by the terminals 32 during this disassembling operation, a centering operation is difficult, with the risk that the terminal pins 26 are likely broken. In order to carry out a terminal header connecting operation, such additional work as the taping of the connected portions to insulate them also becomes necessary. This causes the assembling and disassembling operations to become complicated with an increase of the working steps but with less reliability of the connected portions.